Cerebrospinal fluid glial fibrillary acidic protein, in contrast to amyloid beta protein, is associated with disease symptoms in Huntington's disease.

INTRODUCTION: Huntington's disease (HD) is a hereditary neurodegenerative disease, currently lacking disease-modifying treatments. Biomarkers are needed for objective assessment of disease progression. Evidence supports both complex protein aggregation and astrocyte activation in HD. This study assesses the 42 amino acid long amyloid beta (Aß42) and glial fibrillary acidic protein (GFAP) as potential biomarkers in the cerebrospinal fluid (CSF) of HD mutation carriers. METHODS: CSF from participants was obtained from three sites in Sweden. Clinical symptoms were graded with the composite Unified Huntington's disease rating scale (cUHDRS). Protein concentrations were measured using ELISA. Pearson correlations were calculated to assess disease progression association. Results were adjusted for age and collection site. RESULTS: The study enrolled 28 manifest HD patients (ManHD), 13 premanifest HD gene-expansion carriers (PreHD) and 20 controls. Aß42 levels did not differ between groups and there was no correlation with measures of disease progression. GFAP concentration was higher in ManHD (424 ng/l, SD 253) compared with both PreHD (266 ng/l, SD 92.4) and controls (208 ng/l, SD 83.7). GFAP correlated with both cUHDRS (r = -0.77, p < 0.001), and 5-year risk of disease onset (r = 0.70, p = 0.008). CONCLUSION: We provide evidence that indicates CSF Aß42 has limited potential as a biomarker for HD. GFAP is a potential biomarker of progression in HD. Validation in larger cohorts measuring GFAP in blood and CSF would be of interest.

Levels of inflammatory cytokines MCP-1, CCL4, and PD-L1 in CSF differentiate idiopathic normal pressure hydrocephalus from neurodegenerative diseases.

BACKGROUND: Neuroinflammatory processes have been suggested to play a role in the pathophysiology of neurodegenerative diseases and post-hemorrhagic hydrocephalus, but have rarely been investigated in patients with idiopathic normal pressure hydrocephalus (iNPH). The aim of this study was to investigate whether levels of inflammatory proteins in CSF are different in iNPH compared to healthy controls and patients with selected neurodegenerative disorders, and whether any of these markers can aid in the differential diagnosis of iNPH. METHODS: Lumbar CSF was collected from 172 patients from a single center and represented iNPH (n = 74), Alzheimer's disease (AD) (n = 21), mild cognitive impairment (MCI) due to AD (n = 21), stable MCI (n = 22), frontotemporal dementia (n = 13), and healthy controls (HC) (n = 21). Levels of 92 inflammatory proteins were analyzed using a proximity extension assay. As a first step, differences between iNPH and HC were investigated, and proteins that differed between iNPH and HC were then compared with those from the other groups. The linear regressions were adjusted for age, sex, and plate number. RESULTS: Three proteins showed higher (MCP-1, p = 0.0013; CCL4, p = 0.0008; CCL11, p = 0.0022) and one lower (PD-L1, p = 0.0051) levels in patients with iNPH compared to HC. MCP-1 was then found to be higher in iNPH than in all other groups. CCL4 was higher in iNPH than in all other groups, except in MCI due to AD. PD-L1 was lower in iNPH compared to all other groups, except in stable MCI. Levels of CCL11 did not differ between iNPH and the differential diagnoses. In a model based on the four proteins mentioned above, the mean area under the receiver operating characteristic curve used to discriminate between iNPH and the other disorders was 0.91. CONCLUSIONS: The inflammatory cytokines MCP-1 and CCL4 are present at higher-and PD-L1 at lower-levels in iNPH than in the other investigated diagnoses. These three selected cytokines may have diagnostic potential in the work-up of patients with iNPH.

Case report: a novel deep intronic splice-altering variant in DMD as a cause of Becker muscular dystrophy.

We present the case of a male patient who was ultimately diagnosed with Becker muscular dystrophy (BMD; MIM# 300376) after the onset of muscle weakness in his teens progressively led to significant walking difficulties in his twenties. A genetic diagnosis was pursued but initial investigation revealed no aberrations in the dystrophin gene (DMD), although immunohistochemistry and Western blot analysis suggested the diagnosis of dystrophinopathy. Eventually, after more than 10 years, an RNA analysis captured abnormal splicing where 154 nucleotides from intron 43 were inserted between exon 43 and 44 resulting in a frameshift and a premature stop codon. Normal splicing of the DMD gene was also observed. Additionally, a novel variant c.6291-13537A>G in DMD was confirmed in the genomic DNA of the patient. The predicted function of the variant aligns with the mRNA results. To conclude, we here demonstrate that mRNA analysis can guide the diagnosis of non-coding genetic variants in DMD.

Genetic screening for Huntington disease phenocopies in Sweden: A tertiary center case series focused on short tandem repeat (STR) disorders.

OBJECTIVE: To perform a screening for Huntington disease (HD) phenocopies in a Swedish cohort. METHODS: Seventy-three DNA samples negative for HD were assessed at a tertiary center in Stockholm. The screening included analyses for C9orf72-frontotemporal dementia/amyotrophic lateral sclerosis (C9orf72-FTD/ALS), octapeptide repeat insertions (OPRIs) in PRNP associated with inherited prion diseases (IPD), Huntington's disease-like 2 (HDL2), spinocerebellar ataxia-2 (SCA2), spinocerebellar ataxia 3 (SCA3) and spinocerebellar ataxia-17 (SCA17). Targeted genetic analysis was carried out in two cases based on the salient phenotypic features. RESULTS: The screening identified two patients with SCA17, one patient with IPD associated with 5-OPRI but none with nucleotide expansions in C9orf72 or for HDL2, SCA2 or SCA3. Furthermore, SGCE-myoclonic-dystonia 11 (SGCE-M-D) and benign hereditary chorea (BHC) was diagnosed in two sporadic cases. WES identified VUS in STUB1 in two patients with predominant cerebellar ataxia. CONCLUSIONS: Our results are in keeping with previous screenings and suggest that other genes yet to be discovered are involved in the etiology of HD phenocopies.

Higher levels of neurofilament light chain and total tau in CSF are associated with negative outcome after shunt surgery in patients with normal pressure hydrocephalus.

BACKGROUND: Lumbar punctures are a common examination in the work-up of patients with idiopathic normal pressure hydrocephalus (iNPH) and cerebrospinal fluid (CSF) biomarkers should therefore be available for use in selection of shunt candidates. The aim of this study was to investigate if CSF biomarkers are associated with outcome after shunt surgery alone or in combination with comorbidity and imaging markers, and investigate associations between CSF biomarkers and symptoms. METHODS: Preoperative CSF biomarkers were analyzed in 455 patients operated with shunt surgery for iNPH at a single center during 2011-2018. Symptoms before and 12 months after shunt surgery were graded with the Swedish iNPH scale. Neurofilament light chain protein (NfL), total tau (T-tau), phosphorylated tau (P-tau) and amyloid beta1-42 (Aß1-42) CSF levels were measured. Evans' index and disproportionately enlarged subarachnoid space hydrocephalus were measured on preoperative CT-scans. Preoperative evaluation and follow-up 12 months after shunt surgery were available in 376 patients. RESULTS: Higher levels of NfL and T-tau were associated with less improvement after shunt surgery (ß = - 3.10, p = 0.016 and ß = - 2.45, p = 0.012, respectively). Patients whose symptoms deteriorated after shunt surgery had higher preoperative levels of NfL (1250 ng/L [IQR:1020-2220] vs. 1020 [770-1649], p < 0.001) and T-tau (221 ng/L [IQR: 159-346] vs. 190 [135-261], p = 0.0039) than patients with postoperative improvement on the iNPH scale. Among the patients who improved ≥ 5 levels on the iNPH scale (55%), NfL was abnormal in 22%, T-tau in 14%, P-tau in 6% and Aß1-42 in 45%, compared with normal reference limits. The inclusion of CSF biomarkers, imaging markers and comorbidity in multivariate predictive Orthogonal Projections to Latent Structures (OPLS) models to did not improve predictability in outcome after shunt surgery. CONCLUSIONS: Higher levels of T-tau and NfL were associated with a less favorable response to shunt surgery, suggesting a more active neurodegeneration in this group of patients. However, CSF levels of these biomarkers can be elevated also in patients who respond to shunt surgery. Thus, none of these CSF biomarkers, alone or used in combination, are suitable for excluding patients from surgery.

Proenkephalin Decreases in Cerebrospinal Fluid with Symptom Progression of Huntington's Disease.

OBJECTIVE: Identifying molecular changes that contribute to the onset and progression of Huntington's disease (HD) is of importance for the development and evaluation of potential therapies. METHODS: We conducted an unbiased mass-spectrometry proteomic analysis on the cerebrospinal fluid of 12 manifest HD patients (ManHD), 13 pre-manifest (preHD), and 38 controls. A biologically plausible and significant possible biomarker was validated in samples from a separate cohort of patients and controls consisting of 23 ManHD patients and 23 controls. RESULTS: In ManHD compared to preHD, 10 proteins were downregulated and 43 upregulated. Decreased levels of proenkephalin (PENK) and transthyretin were closely linked to HD symptom severity, whereas levels of 15 upregulated proteins were associated with symptom severity. The decreased PENK levels were replicated in the separate cohort where absolute quantitation was performed. CONCLUSIONS: We hypothesize that declining PENK levels reflect the degeneration of medium spiny neurons (MSNs) that produce PENK and that assays for PENK may serve as a surrogate marker for the state of MSNs in HD. © 2020 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

High frequency of intermediary alleles in the HTT gene in Northern Sweden - The Swedish Huntingtin Alleles and Phenotype (SHAPE) study.

Trinucleotide (CAG) repeat expansions longer than 39 in the huntingtin (HTT) gene cause Huntington's disease (HD). The frequency of intermediate alleles (IA) with a length of 27-35 in the general population is not fully known, but studied in specific materials connected to the incidence of HD. The Swedish Huntingtin Alleles and Phenotype (SHAPE) study aims to assess the frequency of trinucleotide repeat expansions in the HTT gene in north Sweden. 8260 individuals unselected for HD from the counties of Norr- and Västerbotten in the north of Sweden were included. DNA samples were obtained and analysis of the HTT gene was performed, yielding data on HTT gene expansion length in 7379 individuals. A high frequency of intermediate alleles, 6.8%, was seen. Also, individuals with repeat numbers lower than ever previously reported (<5) were found. These results suggest a high frequency of HD in the norther parts of Sweden. Subsequent analyses may elucidate the influence of IA:s on traits other than HD.

Phenotypic variability in chorea-acanthocytosis associated with novel VPS13A mutations.

OBJECTIVE: To perform a comprehensive characterization of a cohort of patients with chorea-acanthocytosis (ChAc) in Sweden. METHODS: Clinical assessments, targeted genetic studies, neuroimaging with MRI, [18F]-fluorodeoxyglucose (FDG) PET, and dopamine transporter with 123I FP-CIT (DaTscan) SPECT. One patient underwent magnetic resonance spectroscopy (MRS). RESULTS: Four patients living in Sweden but with different ethnical backgrounds were included. Their clinical features were variable. Biallelic VPS13A mutations were confirmed in all patients, including 3 novel mutations. All tested patients had either low or absent chorein levels. One patient had progressive caudate atrophy. Investigation using FDG-PET revealed severe bilateral striatal hypometabolism, and DaTscan SPECT displayed presynaptic dopaminergic deficiency in 3 patients. MRS demonstrated reduced N-acetylaspartate/creatine (Cr) ratio and mild elevation of both choline/Cr and combined glutamate and glutamine/Cr in the striatum in 1 case. One patient died during sleep, and another was treated with deep brain stimulation, which transiently attenuated feeding dystonia but not his gait disorder or chorea. CONCLUSIONS: Larger longitudinal neuroimaging studies with different modalities, particularly MRS, are needed to determine their potential role as biomarkers for ChAc.

[Recent advances in Huntington's disease]. / Huntingtons sjukdom ­ kliniska prövningar inger nu optimism - Vanligaste formen av ärftlig neurodegenerativ sjukdom i västvärlden ger svåra symtom och förtidig död.

Huntington's disease is an autosomal dominant neurodegenerative disease that leads to premature death. The disease is caused by a pathological CAG triplet expansion in the huntingtin gene. The disease is most common in Western populations, with onset in middle age and causing progressive motor, cognitive, and psychiatric symptoms. Currently, only symptomatic treatment is provided, but new molecular technologies may allow treatments reducing levels of mutated huntingtin.

Aniridia with PAX6 mutations and narcolepsy.

PAX6 gene mutations cause a variety of eye and central nervous system (CNS) abnormalities. Aniridia is often accompanied by CNS abnormalities such as pineal gland atrophy or hypoplasia, leading to disturbed circadian rhythm and sleep disorders. Less is known on the coincidence of narcolepsy in this patient group. We aimed to find out whether the circadian rhythm or sleep-wake structure was affected in patients with aniridia. Four members of a family segregating with congenital aniridia in two generations were included in the study. The patients were subjected to genetic testing for a PAX6 mutation, multiple sleep latency test, whole-brain magnetic resonance imaging (MRI), hypocretin-1 in cerebrospinal fluid, and Human Leukocyte Antigen DQ beta1*06:02. All four members were heterozygous for the pathogenic c.959-1G>A mutation in the PAX6 gene. Sleep disturbance was observed in all family members. The index patient was diagnosed with narcolepsy. MRI showed a hypoplastic pineal gland in all members. We describe the first case of a patient with PAX6 haploinsufficiency, aniridia and pineal gland hypoplasia diagnosed with narcolepsy type-1, suggesting a complex sleep disorder pathogenesis.

Measurement of sCD27 in the cerebrospinal fluid identifies patients with neuroinflammatory disease.

BACKGROUND: Laboratory tests to assist in the diagnosis and monitoring of neuroinflammatory diseases are scarce. The soluble form of the CD27 molecule (sCD27) is shed in high concentrations by activated T cells and can be detected in the cerebrospinal fluid. The aim of this study was to investigate whether CSF quantitation of sCD27 could discriminate between inflammatory and non-inflammatory neurological diseases. METHODS: The concentration of sCD27 was measured using a commercially available ELISA in 803 well-defined subjects from a study cohort comprised of 338 patients with neuroinflammatory disease, 338 with non-inflammatory neurological disease and 127 controls without neurological disease. RESULTS: The median value of cerebrospinal fluid sCD27 was 64 pg/mL (IQR 0-200) in controls, 58 pg/mL (IQR 0-130) in patients with non-inflammatory disease and 740 pg/mL (IQR 230-1800) in patients with inflammatory disease. The likelihood ratio of having an inflammatory disease was 10 (sensitivity 74% and specificity 93%) if the sCD27 concentration was >250 pg/mL. In patients with a known inflammatory condition, the likelihood ratio of having an infection was 10 (sensitivity 40% and specificity 96%) if the sCD27 concentration was >2500 pg/mL. CONCLUSIONS: The likelihood of having an inflammatory neurological condition is increased with elevated concentrations of sCD27 in cerebrospinal fluid. Rapid tests of sCD27 should be developed to assist clinicians in diagnosis of neuroinflammatory disease.

Alterations in the tyrosine and phenylalanine pathways revealed by biochemical profiling in cerebrospinal fluid of Huntington's disease subjects.

Huntington's disease (HD) is a severe neurological disease leading to psychiatric symptoms, motor impairment and cognitive decline. The disease is caused by a CAG expansion in the huntingtin (HTT) gene, but how this translates into the clinical phenotype of HD remains elusive. Using liquid chromatography mass spectrometry, we analyzed the metabolome of cerebrospinal fluid (CSF) from premanifest and manifest HD subjects as well as control subjects. Inter-group differences revealed that the tyrosine metabolism, including tyrosine, thyroxine, L-DOPA and dopamine, was significantly altered in manifest compared with premanifest HD. These metabolites demonstrated moderate to strong associations to measures of disease severity and symptoms. Thyroxine and dopamine also correlated with the five year risk of onset in premanifest HD subjects. The phenylalanine and the purine metabolisms were also significantly altered, but associated less to disease severity. Decreased levels of lumichrome were commonly found in mutated HTT carriers and the levels correlated with the five year risk of disease onset in premanifest carriers. These biochemical findings demonstrates that the CSF metabolome can be used to characterize molecular pathogenesis occurring in HD, which may be essential for future development of novel HD therapies.

Cerebrospinal fluid sCD27 levels indicate active T cell-mediated inflammation in premanifest Huntington's disease.

INTRODUCTION: Huntington's disease (HD) is a neurodegenerative disorder, but evidence also suggests neuroinflammation in the pathogenesis. The immune mechanisms involved and the timing of their activation need further clarification. METHODS: A clinically well-characterized HD cohort and gene negative controls were enrolled. YKL-40 reflecting innate immunity and sCD27, a marker of adaptive immunity, were measured across disease stages. Comparisons were made with markers of neurodegeneration: neurofilament light (NFL), total-tau (T-tau), and phospho-tau (P-tau). RESULTS: 52 cross-sectional cerebrospinal fluid samples and 23 follow-up samples were analyzed. sCD27 was elevated in manifest HD and premanifest gene expansion carriers, whereas controls mostly had undetectable levels. YKL-40 showed a trend toward increase in manifest HD. sCD27 correlated with YKL-40 which in turn was closely associated to all included markers of neurodegeneration. YKL-40, NFL, and both forms of tau could all independently predict HD symptoms, but only NFL levels differed between groups after age-adjustment. CONCLUSION: Increased sCD27 in premanifest HD is a sign of T cell-mediated neuroinflammation. This finding is novel since other reports almost exclusively have found early involvement of innate immunity. Validation of sCD27 in a larger HD cohort is needed. The role of adaptive immunity in HD needs further clarification, as it may hasten disease progression.

Tau or neurofilament light-Which is the more suitable biomarker for Huntington's disease?

INTRODUCTION: Previous studies have suggested cerebrospinal fluid (CSF) levels of neurofilament light (NFL) and total tau are elevated in Huntington's disease (HD) and may be used as markers of disease stage. Biomarkers are needed due to the slow disease progression and the limitations of clinical assessment. This study aims to validate the role of NFL and tau as biomarkers in HD. METHODS: CSF was obtained from a cohort of HD patients and premanifest HD-mutation carriers. Unified Huntington's Disease Rating Scale (UHDRS) testing was performed on all subjects at the time of sampling. NFL and tau concentrations were determined by ELISA. Spearman correlations were calculated with R version 3.2.3. RESULTS: 11 premanifest HD and 12 manifest HD subjects were enrolled. NFL and tau levels were correlated. NFL showed strong correlations with all items included in the clinical assessment (for example the total functional capacity (TFC) (r = - 0.70 p < 0.01) and total motor score (TMS) (r = 0.83p < 0.01). Tau showed slightly weaker correlations (eg. TMS (r = 0.67 p < 0.01); TFC (r = - 0.59 p < 0.01)). NFL was significantly correlated with 5-year probability of disease onset, whereas tau was not. CONCLUSION: This study strengthens the case for NFL as a useful biomarker of disease stage. NFL was strongly correlated to all evaluated items in the UHDRS assessment. Tau also has a potential for use as a biomarker but correlations to clinical tests are weaker in this study. We suggest that NFL and possibly tau be used in clinical drug trials as biomarkers of disease progression that are potentially influenced by future disease-modifying therapies.

Psychosis in patients with narcolepsy as an adverse effect of sodium oxybate.

AIM: Hypnagogic and hypnopompic hallucinations are characteristic symptoms of narcolepsy, as are excessive daytime sleepiness, cataplexy, and sleep paralysis. Narcolepsy patients may also experience daytime hallucinations unrelated to sleep-wake transitions. The effect of medication on hallucinations is of interest since treatment of narcolepsy may provoke psychotic symptoms. We aim to analyze the relation between sodium oxybate (SXB) treatment and psychotic symptoms in narcolepsy patients. Furthermore, we analyze the characteristics of hallucinations to determine their nature as mainly psychotic or hypnagogic and raise a discussion about whether SXB causes psychosis or if psychosis occurs as an endogenous complication in narcolepsy. METHOD: We present altogether four patients with narcolepsy who experienced psychotic symptoms during treatment with SXB. In addition, we searched the literature for descriptions of hallucinations in narcolepsy and similarities and differences with psychotic symptoms in schizophrenia. RESULTS: Three out of four patients had hallucinations typical for psychosis and one had symptoms that resembled aggravated hypnagogic hallucinations. Two patients also had delusional symptoms primarily associated with mental disorders. Tapering down SXB was tried and helped in two out of four cases. Adding antipsychotic treatment (risperidone) alleviated psychotic symptoms in two cases. CONCLUSION: Psychotic symptoms in narcolepsy may appear during SXB treatment. Hallucinations resemble those seen in schizophrenia; however, the insight that symptoms are delusional is usually preserved. In case of SXB-induced psychotic symptoms or hallucinations, reducing SXB dose or adding antipsychotic medication can be tried.